It is known to embed optoelectronic modules with a transparent embedding material. For example, DE 199 09 242 A1 discloses an optoelectronic module in the case of which a leadframe with an optoelectronic transducer is positioned in a module package and embedded with a transparent, moldable polymer material. Light is coupled in or out by means of an optical fiber, which is coupled to a connecting piece of the module package. On the leadframe there is also the driver device or receiving device for the optoelectronic transducer.
However, the use of embedding materials that are transparent for the respective range of wavelengths has disadvantages to the extent that transparent embedding materials generally have a high coefficient of thermal expansion and accordingly, when there-are great temperature fluctuations, stresses which can damage the sensitive bonding wire connections in particular occur in the package.
It is therefore advantageous in principle to use for embedding or press-molding the components of a module non-transparent polymer materials provided with fillers which produce a favorable coefficient of thermal expansion of the polymer material. A disadvantage of the use of such polymers as an embedding material is that an optical path cannot be created within the embedding material.
A further problem in particular with the use of a non-transparent embedding compound is that, after the embedding, the exact position of the individual components can no longer be easily seen. However, it may be desirable, for example, to determine exactly the position of an optoelectronic transducer in the module.
Comparable problems may also arise with respect to purely electronic modules provided with a plastic package whenever there is the requirement to bring a component of the module into operative connection with the surroundings and, for this purpose, to determine its position exactly.